Global asymptotic stabilization and tracking of asymmetrical underactuated surface vessels

The stabilization and tracking control problems of asymmetric underactuated surface vessel are investigated in this work. For stabilization control, the model of asymmetric underactuated surface vessels is first converted to two subsystems by coordinate and input transformations, a simple smooth time-varying stabilization control law is then derived by constructing a Lyapunov-like function, achieving global uniform asymptotic convergence of the state trajectory to origin. For trajectory tracking control, the tracking error model is derived, and is converted to two subsystems by coordinate and input transformations, the tracking control law is then constructed based on back-stepping approach, guaranteeing global κ-exponential convergence of the state trajectory to the reference one under mild persistent exciting conditions of the reference trajectory. The effectiveness of the proposed control laws is verified by simulation examples.